This invention relates to a final drive assembly for crawler vehicles, and more particularly to a final drive assembly having a planetary gear transmission system at its final stage and which can provide output from the carrier.
There have heretofore been known a great many final drive assemblies of the kind specified, some of which have a planetary gear transmission system at the final stage thereof. The type of planetary gear transmission system is sun-gear input, fixed ring gear and carrier output.
These final drive assemblies are, however, disadvantageous in that since the carrier and the track-chain-driving sprocket (hereinafter referred to simply as sprocket) are secured almost rigidly by means of tapered serrations or bolts, the carrier must rotate together with the sprocket on the same axis and the external force and the tractive reaction force become so large as to cause a deformation of a housing carrying the sprocket, and when the sprocket axis deviates from its normal axis by any reason or due to a working error, there will occur a deviation of the axis of the carrier which is normally the same as that of the carrier.
In such prior art device, when the carrier deviates from the axis of the planetary gear transmission system beyond a certain value, the load distribution on individual planet gears will become uneven to some degree thereby impairing the durability of the planetary gear transmission system itself.